The config file

Mon, 06 Apr 2026 00:00:00 +0000

A connection pool size of 10 is a guess. A connection pool size of 37 is a scar. Someone ran out of connections on a Tuesday afternoon, tried 50, watched latency spike, backed off to 40, still too high, landed on 37 after a week of graphs, and committed it with “tune pool size.” The code says what happens. The config says what happened.

Nobody talks about config though. Not the twelve-factor app kind, not the “should we use YAML or TOML” kind. The actual values. The numbers someone picked and committed without a PR description, three years ago, that are still running in production.

Running Node.js in production

Wed, 29 May 2013 00:00:00 +0000

We’ve been running Node.js in production since the 0.4 days. The language is easy to get started with. Keeping it running under real traffic is a different problem.

Process management

The application needs to start at boot, restart on crash, and respond to system signals. Upstart handles this on Ubuntu without additional dependencies:

description "myserver"

env APP_HOME=/var/www/myserver/releases/current
env NODE_ENV=production
env RUN_AS_USER=www-data

start on (net-device-up and local-filesystems and runlevel [2345])
stop on runlevel [016]

respawn
respawn limit 5 60

pre-start script
 test -x /usr/local/bin/node || { stop; exit 0; }
 test -e $APP_HOME/logs || { stop; exit 0; }
end script

script
 chdir $APP_HOME
 exec /usr/local/bin/node bin/cluster app.js \
 -u $RUN_AS_USER \
 -l logs/myserver.out \
 -e logs/myserver.err >> $APP_HOME/logs/upstart
end script

respawn limit 5 60 prevents a crash loop – if the process dies 5 times within 60 seconds, Upstart stops trying. The pre-start script verifies that Node and the log directory exist before attempting to start.

Production on vnykmshr

The config file

Running Node.js in production

Process management